Sewing machine



' c. w. MUELLER SEWING MACHINE Filed May 18, 1937 6 Sheets-Sheet lChar/3 IKMuel/er W Gum/M41114 Oct. 31, 1939.-

c. w. MUELLER SEWING MACHINE Filed May 18, 1957 6 Sheets-Sheet 231441014406 Char/e3 W Mae/A97" awn/WM;

Oct. 31, 1939. c. w. MUELLER 2,178,183

SEWING MACHINE Filed May 18, 1937 6 Sheets-Sheet 3 Fi/g. 5.

Char/es 14/. Mud/er Oct. 31, 1939.

C. W.- MUELLER SEWING MACHINE e sheets-sheet 5 Filed May 18, 1937 Oct.31,1939. I c. WMUELLER 2,178,183

SEWING MACHINE Filed May 18, 1957 6 Sheets-Sheet 6 Char/es 14 MqeflerPatented Oct. '31, 1939 UNITED STATES SEWING MACHINE Charles W. Mueller,St. Louis, Mo., assignor to Lewis Invisible Stitch Machine Company, St.Louis, Mo., a corporation of Maine Application May 18, 1937, Serial No.143,387

11 Claims.

This invention relates to new and useful improvements in sewing machinesgenerally, although more particularly to blind stitch sewing machines.

Among the objects of the invention is to provide a main frame having alaterally extending arm which terminates in a removable forwardlyextending arm, the former having a main shaft journaled therein and thelatter having -a main shaft extension journaled therein and having areadily separable clutch connection with the adjacent end of the mainshaft, the forwardly extending arm containing the stitch forming andfabric feedinginstrumentalities which are driven from the main shaftextension and are removable together with the arm as a unit fromthelaterally extending arm.

Another object of the invention is to provide a rotary hook at the freeend of the forwardly extending arm and a driving shaft for the hookwhich is operatively connected with the main shaft extension and isalso'housed within said arm.

Another object of the invention is to provide a main shaft which rotatesaway from the operator and a reciprocatory lever mounted in theforwardly extending arm and operated from the main shaft for taking upthe needle thread and for setting the next to the last formed stitch.

A further object of the invention is to provide an oil bath for thelinkage which operates the take-up lever.

With these and other objects in view which will more fully appear, thenature of the invention will be more clearly understood by following thedescription, the appended claims, and the several views illustrated inthe accompanying drawings.

In the drawings:

Figure 1 is a top plan view of a sewing machine constructed inaccordance with my invention,

Figure 2 is a left hand elevation thereof,

Figure 3 is a right hand elevation of the machine, the forwardlyextending arm being shown in section, 3

Figure 4 is a horizontal section taken through the horizontal arm andthe adjacent end of the laterally extending arm, the arms being shown inseparated relation, V, Figure 5 is a detail rear elevation of theforwardly extending arm, I

Figure 6 is a detail vertical section taken through the oil housing,

Figures 7, 8, 9 and 10 are detail views showing the take-up lever indifferent positions,

Figure 11 is a perspective view of the feed dog,

Figure 12 is a perspective view of the front end of the feed dog withoutthe vertically yieldable clamping portion, V

Figure 13 is a bottom perspective view of the feed dog,

Figures 14 and 15 are diagrammatic views showing the speed travel of thetake-up lever,

Figure 16 is an enlarged plan view of the foot showing the relationbetween the needle, the needle thread, the bobbin thread, and the feeddog when the latter is at the forward end of its 16 stroke,

Figure 17 is a similar view but showing the feed dog at the rear end ofits stroke,

Figure 18 is a bottom plan view of the foot,

Figure 19 is a perspective view of the cloth retainer, and

Figure 20 is a perspective view of the edge guide.

Like reference numerals designate corresponding parts throughout theseveral figures of the drawings. I

The sewing machine as shown in the accompanying drawings, includes amain-frame A which comprises a standard 5, a horizontal arm 6 extendinglaterally from the upper end of the standard and terminating in -aforwardly and downwardly extending upper arm I, and a base arm 8 whichextends laterally from the lower end of the standard and terminates in aforwardly extending base arm 9. The arm I is removably connected at itsrear end to the free end of the arm 6 by screws l0.

A substantially horizontal presser foot B is fixed to the free end ofthe arm 1.

The arm I is hollow and includes a top II, and right and left side walls.12 and I3 respec: tively. Rigidly supported within the arm 1 adjacentthe rear end thereof and in spaced relation to the right hand wall I2,is a housing C for containing a lubricant such as oil. This housingcomprisesa bottom M, a top 15, front and As shown in Figure 4, a mainshaft 22 is journaled in the horizontal arm 6 and the left end thereofterminates in spaced relation to the free end of said arm. A main shaftextension 23 extends across the rear end of the arm I and has one endjournaled in the side wall l8 of the oil housing C and its other endjournaled in the right hand wall I 2 of the arm. The left hand end ofthe shaft extension 23 projects into the oil compartment C and the righthand end projects into the free end of the arm 6 where it is coupled tothe end of the main shaft by a readily separable clutch 24 having onelarge timing tooth 24 Thus it will be seen that the arm 'I together withthe main shaft extension 23 is removable as a unit from the free end ofthe arm 6.

J ournaled within the arm 'I and extending longitudinally thereof is anoscillatory needle shaft 25. Fixed to the front end of the shaft is aneedle arm 26 which carries a curved needle 21 which reciprocates acrossand above an opening 28 formedin the presser foot B. The rear end of theneedle shaft is operatively connected to the main shaft extension 23 bya rock arm 29 rigidly secured to the rear end of the needle shaft, aneccentric 30 fixed to the main shaft extension 23, and a link 3| whichconnects the rock arm with the eccentric. It will be noted that the ec'centric 30 is located between the oil housing C and the right hand walll2 of the arm I, and also that the penetrating stroke of the needle isfrom right to left.

Cooperating with the needle 21 above the foot to form lock stitches, isa rotary hook Dcontaining a bobbin thread E which is mounted on a shaft32 extending transversely of the arm I and journaled-in said armadjacent the front end thereof. The hook shaft 32 is driven from themain shaft extension 23 by a shaft 33 which is journaled in and extendsdiagonally and longitudinally of the arm I, there being a gear coupling34 between the hook shaft 32 and the driving shaft 33 and a gearcoupling 35 between the driving shaft 33 and the main shaft extension23, the coupling 35 including a driving gear 36 fixed to the outer endof said shaft extension. The rear end of the driving shaft is journaledin the upper portion of the oil housing C above the main shaft extension23, and consequently the gear coupling 35 is located within the, oilcompartment of the housing.

Mounted on the base arm 9 of the frame directly below the presser foot Bis a post F, and supported on this post is an oscillatory ridge formingelement G for projecting a ridge of fabric upwardly through the presserfoot opening 28 into needle penetrating pfitionjtheelement Gbeingoscillated from the main shaft 22 in the usual manner. Also supported bythe post is a vertically yieldable work clamp H which cooperates withthe under face of the presser foot to clamp the fabric against thethrust of the needle.

An intermittent or 4-motion upper feed'dog I is located directly in rearof the needle path and cooperates with the work clamp through theopening 28 in the foot to feed the fabric rearwardly. The feed dog I isfixed to the front end of a feed lever 38 which extends longitudinallywithin the frame arm I. The-lever 38 is fulcrumed intermediate its endsby a vertical link 39 to the wall l2 of the arm I, and the rear end ofthe lever is operatively connected to an adjustable eccentric which isindicated as a whole by the numeral 40. The lever 38 is located slightlybelow the needle shaft 25 and between said shaft and the wall I2 of theframe arm I, the eccentric extension 23.

40 being positioned on the main shaft extension 23 between the needleshaft eccentric 30 and said wall 12. The feed dog I is timed with theneedle 21 so that when the needle has just withdrawn from the fabric,the feed dog is at the beginning of its feed stroke, as shown in Fig.16, and when the feed dog is at the end of its feed stroke the needlehas begun its penetrating stroke, as shown in Fig. 17.

Usually in lock stitch machines, the main shaft is rotated in adirection towards the operator, but in the present case the main shaftis rotated in a direction away from the operator.

The needle thread J is led from any suitable source of supply to astationary thread guide 4l mounted on the rear end of the frame arm I,thence forwardly around a tension 42 mounted on the front end of the armI, thence rearwardly along said arm and through a thread guide oropening 43 formed in the upper end of a take-up lever K, thenceforwardly to a stationary thread guide 44 mounted on the front end ofthe arm I, thence through a thread guide 45 mounted on the needle arm26, and thence to the needle eye.

The take-up lever K is fixed to the right hand end of a horizontal rockshaft 46 which is journaled in the upper portion of the oil housing C infront of the main shaft extension 23. The shaft 46 extends transverselyof the frame arm I and consequently the take-up lever oscillates in avertical plane extending longitudinally of said arm. The lever projectsupwardly through a longitudinally extending slot 41 formed in the arm,and the thread guide or opening 43 is located above said arm. The lefthand end of the rock shaft 46 projects into the oil compartment of theoil housing C and fixed thereon is a downwardly projecting rock arm 48which is oscillated from the main shaft extension 23 by means of thefollowing linkage located Within said oil compartment:

A supporting link 49 is fulcrumed to swing about a stationary pivot 50located below the main shaft A bell crank lever 5| is fulcrumed at itsangle as at 52 to the free end of the supporting link 49. This bellcrank lever includes arms 53 and 54, the former being pivotallyconnected at its free end to an eccentric pin 55 mounted on the gear 36,and the latter being pivotally connected at its free end as at 55 to oneend of a connecting link 51 which is pivotally connected at its otherend as at 58 to the free end of the rock arm 48.

The take-up lever K is swung forwardly to give slack to the needlethread when the needle loop is being passed around the hook, and isswung rearwardly to take-up theneedle thread loop of the last formedstitch and set the next to the last formed stitch.

The forward or slack-giving stroke of the takeup lever occurs during 240of rotation of the main shaft, and the rearward or take-up stroke of thelever occurs during the remaining of rotation of the main shaft. In Fig.14, I have illustrated the speed travel of the take-up lever during itsforward stroke, the line a indicating the length of the stroke and thespaced lines b indicating the distance of travel of the thread guide oropening 43 of the lever during successive movements of 10. In Fig. 15, Ihave illustrated the speed travel of the take-up lever during itsrearward stroke, the line a indicating the length of the stroke and thespaced lines 0 indicating the distance of travel of the thread guide oropening 43 during successive movements of 10. It will therefore be seenthat the speed travel of the thread guide 43 is twice as fast during therear- ,this travel of the pin, the supporting link 49 will beswungupwardly until the floating fulcrum 52 of the bell crank lever willbe in substantial alinement with the longitudinal axis of the mainshaft. Thus it will be seen that the bell crank lever will be elevatedand that the connecting link 51 will cause the take-up lever to be swungforwardly to its half way position 'as shown in said Fig. 8. During thenext 120 movement of the eccentric pin 55, or from the position shown inFig. 8 to the position shown in Fig. 9, the take-up lever willbeswungaforwardly to its extreme forward position, this movement of thetake-up lever being brought about by means of the eccentric pin 55rocking the bell crank lever 5| about its fulcrum 52 which issubstantially stationary during this period.

The eccentric pin 55 then moves downwardly and forwardly and thenupwardly and forwardly from the Fig. 9 position to the Fig. 7 position,

during which time the pin travels 120 and the take-up lever is swungrearwardly to its extreme rear position. During the first part of thismovement, the downward and forward travel of the pin causes thesupporting link!!! to be swung downwardly from the Fig. 9 position tothe Fig. 10 position, and inasmuch as the bell crank lever 5| isfulcrumed on said link said lever will be bodily moved downwardly andforwardly. This movement of the bell crank lever, through the medium ofthe connecting link 51, causes the take-up lever to be swung rearwardlytoits half way position as shown in said Fig. 10-. Upon continuedmovement of the pin, the bell crank lever will be 'rocked on its fulcrum55 and consequently the arm 54 of said lever will be swung downwardlyand the connecting link 51 willcause the take-up lever to be swung toits extreme rear position as shown in Fig. '7.

When the needle in moving forwardly is about to enter the hem fold, thetake-uplever will begin its forward stroke to give slack to the needlethread. The *r'reedle completes its' forward or penetrating stroke andwithdraws from the hem,

while the needle is partaking of the first portion of its forward orpenetrating stroke, the take-11D lever is completing its backward strokeand functions to further take-up the needle thread loop of said lastformed'stitch and to set the next to 'the last formed stitch. It willtherefore be apparent that if the next to the last formed stitches areset too tight, it willresult in puckering the fair side of thebodyfabrio which of course is objectionable.

begins its backward or take-up stroke. up lever- 'bobbin', against thefabric.

I have overcome this objection by providing the feed dog I with a frontsection which functions to clamp the bobbin thread extending diagonallyfrom the next-to-last formed stitch to the bobbin against the fabricduring the take-up movement of thetake-up lever whereby sufficient slackin the laid bobbin thread will suflice.

to prevent the puckering effect above noted.

To this end, the feed dog. I includes a body portion 59 having a steppedfront portion forming, a resultant toe 60 which projects forwardly fromthe right hand corner thereof, a recess Bl which is located at the lefthand corner of the body portion, and a front transverse wall or edge 62which merges with said toe and recess. The

' upper face of the body portion is milled to form and the section 66being located on the right hand side of the body portion and extendingunder the toe 60, the front end of the groove 61 merging with the frontwall 62. A vertically yieldable thread clamping section 68 is positionedin the recess GI and the under face 69 thereof is smooth and is normallydisposed slightly below the plane of the feed sections 65, 6G. Theclamping section 68 is supported on the body portion 59 of the footthrough the medium of a rearwardly extending spring arm 10 which restson the bearing surface-63 and is secured to the body portion by a screwII, the rear edge 12 of the arm abutting the shoulder 64 to retain thesectio against turning. a

The take-up lever K, the'needle 21, and the feed dog I, are timed asfollows: When the needle leaves the fabric on its backward stroke, thefeed begins its feeding stroke, and the take-up lever The takeovesrearwardly during the feed stroke of the dog, is its rearward movementstops at an instant before the completion of' said feed stroke; It willbe observed, as shown in Fig. 16, that the section S8 of the feed dogwhen at the beginning of its feeding stroke, is clamping the bobbinthread E, which extends diagonally from the next to last formed needlethread loop to the Consequently this portion of the bobbin thread willbe clamped by the feed dog during the feeding stroke thereof and whilethe takeup lever K ismoying rearwardlyto take up the needle loop, thefeed dog releasing the bobbin thread an instant before the lever reachesthe rear end of its stroke, as shown in Fig. 17, whereby the next tolast needle thread loop will be set but without taking up the slackbobbin thread which extends between the last an edgeguide M on the clothretainer for transverse adjustments relative thereto. The foot isprovided at its front end with a bearing lug 13' on the right of theopening 28 of the foot. Mounted in this lug is a horizontally disposedsplit bushing 14 of steel which projects laterally to form. an extendedbearing. A rock shaft is journaled in the bearing and is provided at itsinner end with an eccentric pin 16. The shaft 15 can be adjusted aboutits axis to alter the position of the eccentric pin 16, and a set screw18 is threadably engaged in the outer end of the bushing to retain theshaft in an adjusted position. The cloth retainer L is formed of thinspring steel, and the front end is provided with spaced bearing eyes 19,I9 which are journaled on the eccentric pin 16, and are retained thereonby a screw which is threaded into the end of the pin. The cloth retainerextends rearwardly into the presser foot opening .28 directly above theridge forming element G, and the rear edge of the retainer is locatedimmediately in front of the needle path, the retainer having a portionwhich overhangs the left edge of the presser foot opening and bearsagainst the upper face of the foot to limit the downward movement ofsaid retainer. A coil spring al is disposed around the eccentric pin 16between the bearing eyes 19, 19 of the retainer, one end of the springbearing downwardly upon the retainer and the other end being anchored ina slot 82 of the bushing. It will therefore be seen that the springyieldably holds the retainer against the ridge of fabricwhich is formedby the ridge forming element G, and consequently said ridged fabric isheld by the retainer against the thrust of the needle and ,also againstbeing moved forwardly towards the operator when the oscillatory ridgeforming disc hand edge of the retainer L. From the above, it

will be observed that the retainer L can be adjusted towards or from theneedle path to meet different working conditions; that the edge guide Mwill be adjusted therewith, and that the edge guide is adjustabletransversely relative to the retainer.

It is of course to be understood that the details of structure andarrangement of parts may be variously changed and modified withoutdeparting from the spirit and scope of my invention.

I claim:

1. In a sewing machine, a main frame includ ing a standardard having anarm extending laterally therefrom, a main shaft journaled in said arm, aforwardly extending frame arm detachably connected at its rear end tothe free end of the laterally extending arm, and a main shaft extensionjournaled in the rear. end of the forwardly extending arm and having oneend detachably clutched to the adjacent end of the main shaft wherebythe arm together with the main shaft extension may be detached as a unitfrom the laterally extending arm.

2. In a sewing machine, a main frame including a standard having an armextending laterally therefrom, a main shaft journaled in said arm andhaving its inner end terminating in spaced relation to the free endthereof, ,a forwardly extending frame arm detachably connected at itsrear end to the free end of the laterally extending arm, and a mainshaft extensionjournaled in from the laterally extending arm.

3. In a sewing machine, a main frame including a standard having an armextending laterally therefrom, a main shaft journaled in said arm, aforwardly extending frame arm detachably connected at its rear end tothe free end of the laterally extending arm, stitching instrumentalitiesmounted on the freeend of the forwardly extending arm, and means mountedin said forwardly extending arm for operating said instrumentalitiesfrom the main shaft including a main shaft extension journaled in therear end of the forwardly extending arm and having one end detachablyclutched to-the adjacent end of the main shaft whereby the arm togetherwith the stitching instrumentalities and said operating-means may bedetached as a unit from the laterally extending arm.

4. In a sewing machine, a main frame including a forwardly extendingarm, a rotary driving shaft journaled in the rear end of said arm andextending transversely thereof, a reciprocatory needle and a cooperatingrotary hook mounted on the front end of said arm, and separate drivingconnections between the shaft and said needle and hook, said connectionsbeing wholly disposed within the arm.

5. In a sewing machine, a main frame including a forwardly extendingarm, a rotary, driving shaft journaled in the rear end of said arm andextending transversely thereof, a reciprocatory needle and a cooperatingrotary hook mounted on the front end of said arm, and separate drivingconnections between the shaft and said needle and hook, said connectionsbeing wholly disposed within the arm and including an oscillatory needleshaft journaled in the arm and extending longitudinally thereof, and arotatable hookdriving shaft journaled in the arm and extendinglongitudinally thereof.

6. In a sewing machine, a main frame including a forwardly extendingarm, a rotary driving shaft journaled in the rear end of said arm andextending transversely thereof, stitch forminginstrumentalities-including a reciprocatory nee dle mounted on the frontend of said arm, an oscillatory take-up lever for the needle threadmounted on said arm, operating connections between said shaft and saidlever, and a lubricantcontaining housing mounted on said arm andcontaining said operating connections.

7. In a sewing machine, a main frame including a forwardly extendingarm, a rotary driving shaft journaled in the rear end of said arm andextending transversely thereof, stitch forming in strumentalitiesincluding a reciprocatory needle mounted on the front end of said arm,said arm being provided with a longitudinally extending slot, anoscillatory take-up lever for the needle driving shaft located inthe-rear end of said arid said shaft being joumaled in the housing andthe other end being iournaled in said side wall of said arm, anoscillatory needle shaft journaled in said arm and extendinglongitudinally thereof, a needle fixed to the forward end of said needleshaft, driving connections between the rear end of said needle shaft andsaid driving shaft, a rotary hook mounted on the front end of said armfor cooperation with the needle, 8. driving gear fixed to the drivingshaft and located within the housing, driving connections between saidhook and said gear, an oscillatory take-up lever for the needle threadmounted in said arm, and operating connections between said driving gearand said lever, said connections being located within said housing.

9. In a sewing machine, a main frameincluding a laterally extendinghollow arm having a top and a side wall, a lubricant-containing housingmounted in the rear end of said arm, a rotary driving shaft located inthe rear end of said arm and extending transversely thereof, one end ofsaid shaft being journaled in the housing and the other end beingJournaled in said side wall of said arm, an oscillatory needle shaftjournaled in said arm and extending longitudinally thereof, a needlefixed to the forward end of said needle shaft, driving connectionsbetween the rear end of said needle shaft and said driving shaft, arotary hook mounted on the front end of said arm for cooperation withthe needle, 0.

driving gear fixed to the driving shaft and located within the housing,driving connections between said hook and said gear, an oscillatorytake-up lever for the needle thread mounted in said arm, an eccentricpin rotatable with said gear, and operating linkage between saideccentric pin and said lever, said linkage being located within saidhousing. 4

10. In a sewing machine, a needle thread takeup mechanism comprising arotary shaft, a rock shaft, a take-up lever fixed to said rock shaft,and driving connections between said shafts comprising an eccentricmounted on the rotary shaft, a rock arm fixed to the rock shaft, a bellcrank lever having a shiftable fulcrum, one arm of the bell crank leverhaving pivotal connection with the eccentric, and a link connecting theother arm of the bell crank lever with the rock arm.

11. In a sewing machine, a needle thread takeup mechanism comprising arotary shaft, a rock shaft, a take-up lever fixed to said rock shaft,and driving connections between said shafts comprising an eccentricmounted on the rotary shaft. a rock arm fixed to the rock shaft, asupporting link rockable about a fixed fulcrum, a bell crank leverfulcrumed on said supporting link, one arm of the bell crank leverhaving pivotal connection with the eccentric, and a link connecting theother arm of the bell crank lever with the rock so CHARLES W. Mum-m2.

